1. Field of the Invention
The subject invention relates to methods and apparatus for printing information on a sheet of material, such as by means of a dot-matrix print head or other printing device.
2. Disclosure Statement
The following disclosure statement is made pursuant to the duty of disclosure imposed by law and formulated in 37 CFR 1.56(a). No representation is hereby made that information thus disclosed in fact constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends on uncertain and inevitably subjective elements of substantial likelihood and reasonableness, and inasmuch as a growing attitude appears to require citation of material which might lead to a discovery of pertinent material though not necessarily being of itself pertinent. Also, the following comments contain conclusions and observations which have only been drawn or become apparent after conception of the subject invention or which contrast the subject invention or its merits against the background of developments which may be subsequent in time or priority.
A frequent requirement in the use of dot-matrix print heads and other printing devices is that a certain narrow gap be provided between the active portion of the print head or other printing device and the platen used to back up the paper or other sheet of material onto which information is printed. As the leading edge of the sheet enters such narrow gap, jams tend to occur, especially if the edge of the entering sheet is not perfectly flat.
In an effort to overcome this disadvantage, it has been proposed to position a flat platen at a wide gap from from the print head, and to enter the sheet into such wide gap. Either the head or the flat platen are then translatorily moved with an actuator so as to close the gap between the head and the platen down to a working distance, keeping the entered sheet at the requisite close range to the print head.
The mechanism required to accomplish the latter task tends to be complex and is prone to wear and misadjustment. Such problems generally are aggravated in the case of modern printing methods wherein the entering sheet is moved into position at the print head at a rate consistent with printing speed.